Went through this thread (for about the 10th time) as Dave may add it to the FAQ Forum and found an error on p. 4
"In 1989, all proof data was marked in metric using the BAR as the unit of measurement. The use of kilograms per square centimetre was dropped. Under this system, 850 bar represented standard proof, with 1200 bar being special or magnum. 2 1/2" chambered guns are usually proofed 850 bar (3 tons per sq. inch)
2 3/4" chambered may be proofed 900 bar (3 1/4 tons per sq. inch) or higher."
This should read:
In 1989, all proof data was marked in metric using the BAR as the unit of measurement. The use of TONS per square inch was dropped. Under this system, 850 bar represented standard proof, with 1200 bar being special or magnum. 2 1/2" chambered guns are usually proofed 850 bar and 2 3/4" chambered may be proofed 900 bar or higher.
I interpret all this to mean that the SAAMI psi conversion for the 1954 TONS measurement is different from the 1989 BAR measurement.
BOTTOM LINE: ANY 850 BAR (proof) = 650 BAR service or 3 TON service gun should be fine at pressures under 8500 psi, or 3 1/4 tons less than 9,500 psi.
Last edited by revdocdrew; 04/27/07 02:57 PM.
